1. Field of the Invention
This invention relates to an industrial truck, such as a counterweighted fork-lift truck, with a vehicle frame that has a frame segment with a lateral frame opening that is realized so that it can hold a battery block. To cover the frame opening, a door is provided that can be pivoted outwardly around an essentially vertical axis of rotation. The door is connected with the vehicle frame by a double hinge, wherein a second axis of rotation is oriented parallel to and located at some distance from the first axis of rotation. During rotation, the door is movable around the first axis of rotation, by which, when the door is in the closed position, an intermediate leaf of the door that is located between the axes of rotation can be blocked in position with respect to an adjacent main leaf.
2. Technical Considerations
An industrial truck is described in DE 103 42 659 A1. On this truck, the double hinge makes it possible to pivot the door in a pivoting range between the closed position and an opening position that is at an approximately right angle to the closed position around the first axis of rotation, and to pivot the door around a second axis of rotation in the pivoting range beyond that. The position of the second axis of rotation makes it possible to achieve an opening angle of the door of 180 degrees, even when there is a counterweight that projects laterally from the frame of the truck. In other words, as a result of the positioning of the second axis of rotation at a distance from the first axis of rotation, a collision of the door with the counterweight (or any other components that may project laterally) of the industrial truck can be prevented. In the closed position, the door therefore fits flush into the lateral contour of the vehicle, i.e., it does not project laterally.
This construction makes it possible for the battery block to be installed and/or removed by a second fork-lift truck. To perform this task, the second fork-lift truck drives so that its fork carrier on which the fork arms are held is as close as possible to the side wall of the vehicle frame, so that it can pick up the battery block. This position is possible without interference because the folding door is in the 180-degree open position.
Because the door and the double hinge are realized so that they contribute to the rigidity of the frame and can be locked in the closed position by a lock that is capable of transmitting forces, in the closed position the door functions as a part of the vehicle frame and absorbs tensile and compression forces. To prevent a rotation of the door around the second axis of rotation when it is subjected to a compression stress, protection against buckling is provided. The purpose of the protection against buckling is to achieve a defined sequence of movement when the door is opened and closed. For this purpose, when the door is opened, it first pivots around the first axis of rotation, whereby the position of the second axis of rotation changes. Once the door has pivoted beyond 90 degrees, the continued rotation is exclusively around the second axis of rotation, which thereby maintains its position.
In one variant that is simple from a manufacturing point of view, the protection against buckling provided on the industrial truck consists of a manually-actuated locking rod, by means of which a rigid connection can be created between the main leaf of the door and the intermediate leaf of the door, which is bounded by the two axes of rotation of the double hinge.
The locking rod, which between the closed position and the 90-degree open position ensures that pivoting around the second axis of rotation is blocked, is disengaged in the 90-degree open position (in the simplest case, manually). In this position, the second axis of rotation is outside the contour of the vehicle. The door can now be pivoted farther to the 180-degree open position, wherein the pivoting movement takes place around the second axis of rotation.
An object of this invention is to provide an industrial truck of the general type described above but on which the operation of the door is simplified.